Physical activity may add years to your life

If you could convince yourself that spending time exercising is a sound investment in your future, would you be more inclined to make it part of your routine?

Maybe you will after you read this.

A study published Tuesday morning in the American Journal of Preventive Medicine calculates the benefits of moderate to vigorous physical activity in terms of its effect on life expectancy. The news is good for most of us who spend at least 150 minutes a week doing such activities.

Researchers led by Ian Janssen of Queen’s University in Ontario, Canada, drew information from three major U.S. databases — the National Health and Nutrition Examination Survey from2007 to 2010; the National Health Interview Survey and its linked mortality files between 1990 and 2006; and U.S. Life Tables from 2006 — to estimate life expectancy for adults who were inactive, somewhat active and active — meaning they engaged in at least 150 minutes of moderate activity each week. Juggling the data, the researchers compared life expectancy among people of different ethnicities and gender and calculated the number of hours of life gained for each hour of activity and also the number of years gained at each age of a person’s life.

In the end, the report focused on the number of years of life a person entering adulthood, at age 20, could be expected to gain if they pursued a lifetime of regular physical activity. For men that amounted to 2.4 years; women who engaged in moderate physical activity added about 3 years to their lives. Non-Hispanic black women who got plenty of physical activity made out best of all, adding about 5.5 years to their lives.

But for reasons the authors couldn’t quite pin down, Hispanics did not appear to realize any longevity benefit related to their physical activity. The authors note that might be because the surveys they based their research on weren’t culturally sensitive enough to capture information about physical activity that might be common among Hispanics but not among whites and blacks.

The authors deliberately opted to present their findings in terms of years of life expectancy gained through physical activity, not years of life lost through inactivity. “Simple messages on changes in life expectancy are more easily understood than relative risk estimates and might influence physical activity behaviors,” they write.

My husband used to tease me that any hours of life I might gain through my dedication to physical activity would equal the number of hours I spend in the gym and yoga studio, making the whole thing a wash. Well, apparently he was wrong. The new study concludes that “non-Hispanics can expect to gain 2.3–5.6 hours of life for every hour of moderate physical activity, and 5.2–11.3 hours of life for every hour of vigorous physical activity they accumulate during adulthood.”